Written by Linda Pransky, a well-known counselor and therapist, A Book About Happiness explores moods in young children. The story follows Cal the Cat as he finds himself feeling down and unhappy more and more. He spends a lot of time trying to figure out why he is so unhappy, when he knows he used to be a happy cat. Eventually, Cal realizes his happiness is inside of him, it always has been and it always will be. He was simply experiencing a temporary bad feeling, which will go away on it's own if he leaves it alone. This book is based on a revolutionary approach to psychology called the three principles, first discovered by a man named Sydney Banks.